The present invention relates to an end packing for a deflection compensated roll, said roll comprising a stationary shaft and a roll shell, bearing-mounted rotatably therearound and having each end thereof provided with a shaft-enclosing annular end cap, having its surface internal in the axial direction of the roll or its surface external in the axial direction formed with a sealing surface, and shaft-mounted bearing elements in each axial end zone of the roll shell inside the end cap. In a second aspect, the invention relates also to an end packing for a deflection compensated roll, said roll comprising a stationary shaft and a roll shell bearing-mounted rotatably therearound and having each end thereof provided with a shaft-enclosing annular end cap, having an external surface and an internal surface in the axial direction of the roll, said internal surface being formed with a sealing surface, and shaft-mounted bearing elements in each axial end zone of the roll shell inside the end cap, the roll end packing elements being mounted on the shaft in a section between the end cap and the bearing elements for a sealing contact against the sealing surface of the end cap. In a third aspect, the invention relates also to an end packing for a deflection compensated roll, said roll comprising a stationary shaft and a roll shell bearing-mounted rotatably therearound and having each end thereof provided with a shaft-enclosing annular end cap, having its surface which is internal in the axial direction of the roll formed with a sealing surface, and shaft-mounted slide bearing elements in each axial end zone of the roll shell inside the end cap, said slide bearing elements comprising radial slide bearing elements and axial slide bearing elements.
FIG. 1 shows one currently available packing system for sealing the end of a roll shell 2 mounted with bearings rotatably around a roll shaft 1. The bearing elements consist of a roller bearing 9. The roll shell has its axial ends provided with an end cap 3, including projections 6 and 7 extending outward in the axial direction of the roll, the inner projection 7 having its outer surface constitute a sealing surface for packing elements 8 which are mounted on a body member 4 secured to the shaft 1. The body member 4 is further provided with chute elements 5 for collecting the oil seeping through the packing. A problem in this system is that the packing may leak quite easily, i.e. it does not function properly as intended. U.S. Pat. No. 6,004,249 discloses an end packing assembly for a roll, comprising a roll shell mounted rotatably around a stationary shaft by means of slide bearings. This assembly includes first packing elements, comprising a spring-loaded packing member which is compressible against an internal end cap surface substantially perpendicular to the longitudinal axis of the roll shaft. In addition, this assembly includes second packing elements, comprising a chamber provided on a roll shaft or in an end cap, in which is fitted a radially movable ring-shaped packing plate provided with a sealing lip setting against a complementary surface. This is a comparatively complex assembly, which is difficult to implement in practice.
Thus, it is an object of the present invention to provide an improved end packing for a deflection compensated roll, said end packing being relatively simple in construction and reliable in operation. In order to accomplish this object, an end packing of the invention for a deflection compensated roll, said roll comprising a stationary shaft and a roll shell bearing-mounted rotatably therearound and having each end thereof provided with a shaft-enclosing annular end cap, having its surface internal in the axial direction of the roll or its surface external in the axial direction formed with a sealing surface, and shaft-mounted bearing elements in each axial end zone of the roll shell inside the end cap, is characterized in that the end packing elements are provided with an annular packing member extending around the shaft and comprising a front face, which is directed towards said sealing surface and which is in contact with the sealing surface or separated from the sealing surface by a gap constituting an axially directed narrow slot, said packing member being provided with elements connected to a supply of compressed air for delivering compressed air into a cavity between the packing member and the sealing surface, whereby the compressed air striving to flow between the packing member""s front face and the sealing surface into and out of the roll functions as a seal.
According to the second aspect of the invention, the invention relates also to an end packing for a deflection compensated roll, said roll comprising a stationary shaft and a roll shell bearing-mounted rotatably therearound and having each end thereof provided with a shaft-enclosing annular end cap, having an internal surface in the axial direction of the roll formed with a sealing surface, and shaft-mounted bearing elements in each axial end zone of the roll shell inside the end cap, the roll end packing elements being mounted on the shaft inside the end cap for a sealing contact against the sealing surface of the end cap, said end packing being characterized in that the packing elements include a labyrinth ring mounted on the shaft, which comprises a packing member compressible against a sealing surface and provided with sealing lips setting against the sealing surface, between which is a cavity opening towards the sealing surface, and that the labyrinth ring is provided with a bore, whereby the cavity of the packing member can be supplied with compressed air from a compressed air duct present in the shaft.
According to the third aspect of the invention, the invention relates also to an end packing for a deflection compensated roll, said roll comprising a stationary shaft and a roll shell mounted with bearings rotatably therearound and having each end thereof provided with a shaft-enclosing annular end cap, having its surface which is internal in the axial direction of the roll formed with a sealing surface, and shaft-mounted slide bearing elements in the area of each axial end of the roll shell inside the end cap, said slide bearing elements comprising radial slide bearing elements and axial slide bearing elements, whereby the roll end packing elements are mounted in connection with the shaft inside the end cap for a sealing contact against the sealing surface of the end cap, said end packing for a slide-bearing fitted roll being characterized in that the packing elements include a sealing ring linked to the bearing shoes of the axial slide bearing elements and located in radial direction inside said bearing shoes, said sealing ring being provided with a cavity opening toward the end cap sealing surface and connected a supply of compressed air, said sealing ring being separated from the end cap sealing surface by an axial gap constituting a narrow slot, said slot allowing compressed air to flow inside the roll and out of the roll.